That's because an overly repressive response to it - the so-called "security-first" approach - had only made matters worse in recent years, she told the Human Rights Council.

"The negative impact of heavy-handed counter-terrorism responses in the years following 9/11, have widened the rift between communities, deepened distrust and generated divisive, often hateful, public discourse."

The Deputy High Commissioner's comments followed a recorded video message to the Geneva assembly by UN Secretary-General Ban Ki-moon in which he said that countering violent extremism needed to avoid "sweeping definitions" that encroached on human rights.

In light of the threat to society posed by extremism today, it is more important than ever to respect freedom of religion, belief and opinion, Kate Gilmore said.

At the same time, civil society's role in voicing the concerns of all people should also be promoted, the aim being to avoid what Gilmore called the "toxic toll" of marginalization.

The Deputy High Commissioner also highlighted that while states are legally responsible for the way they tackle violent extremism, this accountability is in fact the way they will foster public trust.